def sim(now, line):
    m = dict()
    for i in range(1, len(now) + 1):
        no = i
        for x, y in line:
            if no == x:
                no = y
            elif no == y:
                no = x
        # now[i - 1]番は棒noに
        m[no] = now[i - 1]
    to = []
    for k, v in sorted(m.items()):
        to.append(v)
    return to


def solve(now, target):
    ans = []
    t = target[-1]
    n = now.index(t) + 1
    for i in range(n, len(target)):
        ans.append((i, i + 1))

    return ans


def main():
    n = int(input())
    k = int(input())
    l = []
    for _ in range(k):
        x, y = map(int, input().split())
        l.append((x, y))
    target = list(map(int, input().split()))

    now = list(range(1, n + 1))
    now = sim(now, l)

    ans = []
    while True:
        new = solve(now, target)
        ans += new
        now = sim(now, new)

        now = now[:-1]
        target = target[:-1]
        if len(now) == 1:
            break

    print(len(ans))
    for a in ans:
        print(a[0], a[1])

if __name__ == '__main__':
    main()